Question 18460
 From
 (x+1)(x-7)>0

 two roots of (x+1)(x-7) =0
 are 7 and -1.


 Use your eyes,you can directly see the solution set is (7,+oo) U (-oo,-1). 
 (union of two open intervals)
 

 This kind of simple question is not for me.  

 Since another answer is incomplete(wrong), I just show you the
 right answer.

 Kenny